Apparatus for loading wafers and method for loading wafers using the same

ABSTRACT

The present invention relates to an apparatus for loading wafers, a semiconductor manufacturing apparatus and a method for loading wafers comprising: a disk pad for supporting a wafer, the disk pad having a fixing member mounted on a front surface thereof for fixing the wafer and a hole extending therethrough; and a pusher positioned at the back of the disk pad, the pusher having a pushing member for moving the fixing member and a sensing member for sensing a contact between the disk pad and the wafer. According to the present invention, it is possible to exactly determine if a wafer is adhered closely to a disk pad by a sensor before regular processes are performed. Accordingly, an expected wafer loss during a process at an unstable wafer clamping state can be minimized or avoided. Resultantly, productivity or yield of a semiconductor chip can be improved.

CROSS-REFERENCE TO RELATED APPLICATIONS

This U.S. non-provisional patent application claims priority under 35 U.S.C. § 119 of Korean Patent Application 2004-58755 filed on Jul. 27, 2004, the entire contents of which are hereby incorporated by reference.

BACKGROUND

The present invention relates to an apparatus and method for loading wafers, more particularly, to an apparatus and method for loading wafers in a semiconductor manufacturing apparatus which is capable of decreasing or avoiding wafer loss.

High energy ion implantation apparatuses from a semiconductor manufacturing apparatus can include an arm for loading and unloading a wafer to a disk pad located on a disk in a vacuum cassette. When the arm moves the wafer to the disk pad, the wafer is moved to a vertical position.

At this time, as shown in FIG. 1, fixing a wafer W on a disk pad 20 is accomplished by clamping the wafer W at edges of the disk pad 20 with a clamp 22. A circular and rumple-like silicon pad 23 is adhered on a front surface of the disk pad 20 on which a wafer W is placed. However, the clamp 22 may clamp the wafer W such that the wafer W is unstably adhered to the disk pad 20. At this state, the clamp 22 holding the wafer W may lose the wafer W when the disk is rotated. The productivity or yield of semiconductor chips can be substantially decreased due to this wafer loss.

In a conventional method, degree of adherence of a wafer to a disk pad is detected by the naked eyes of a user. Therefore, there is a significant difference in determining this adherence degree in accordance with the user's competence or visual power.

SUMMARY

The present invention discloses an apparatus for loading a wafer capable of decreasing a wafer loss by detecting a state of a wafer clamping in advance by a sensor, a semiconductor manufacturing apparatus using the same and a wafer loading method. The subject apparatus for loading a wafer can detect the clamping state of the wafer loaded onto a disk pad in advance, before predetermined processes are performed.

An apparatus for loading a wafer can be provided which comprises a disk pad for supporting a wafer. A member defining a hole can be mounted on a front surface of the disk pad for affixing the wafer to the disk pad. A pusher, positioned at the back of the disk pad, can comprise a pushing member for moving the affixing member and a sensing member for sensing contact between the disk pad and the wafer.

Preferably, the sensing member is located within the hole at a front surface of the disk pad. The sensing member can preferably be in the hole at a higher point than a front surface of the disk pad. Moreover, the sensing member can be a contact sensor for determining wafer loading by locating the rear surface of the wafer loaded on the front surface of the disk pad and by defining the relative degree of adhesion of the rear surface of the wafer to the disk pad. The hole is preferably formed at substantially the center portion of the disk pad. The sensing member can be a contact sensor for determining wafer loading by locating the rear surface of the wafer loaded on the front surface of the disk pad and defining the relative degree of adhesion of the rear surface of the wafer to the disk pad. The semiconductor manufacturing apparatus preferably comprises a holder positioned at the front surface of the disk for releasing the wafer from the disk pad.

A wafer loading method can also be provided. The method comprises providing a wafer and a disk pad, transferring the wafer to the disk pad, providing a pusher; moving the pusher toward the back of the disk pad, loading the wafer to the disk pad, and clamping the wafer by moving the pusher from the disk pad until the wafer is adherely engaged with the disk pad. The method can preferably comprise further interlockingly enaging the wafer so that it is more closely adhered to the disk pad. Further preferred steps can include sensing contact between the disk pad and the wafer, and transferring the wafer to the front surface of the disk pad in a substantially vertical position.

Another preferred method for loading a wafer on a front surface of the disk pad using the subject apparatus which can comprise a disk pad for supporting a wafer. The disk pad includes a fixing member mounted on a front surface thereof for fixing the wafer and a hole extending therethrough. A pusher is positioned at the back of the disk pad. The pusher has a pushing member for moving the fixing member and a sensing member for sensing contact between the disk and the wafer. The wafer is transferred to the front surface of the disk pad. The pusher is moved toward the disk pad so that the pushing member of the pusher moves the fixing member to be unclamped. The sensing member is then inserted into the hole to constitute the same surface as the front surface of the disk pad. The wafer is loaded on the front surface of the disk pad. Then, the pusher is moved from the disk pad so that the fixing member fixes the wafer to the front surface of the disk pad, when the sensing member contacts the rear surface of the wafer.

According to the present invention, it is possible to exactly determine if a wafer is adhered to a disk pad by a sensor before an ion implantation process is performed. Accordingly, a wafer loss during an ion implantation process at an unstable wafer clamping state can be minimized or avoided, resulting in improving productivity or a yield of a semiconductor chip.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view illustrating a prior art wafer loading apparatus;

FIG. 2 is a perspective view illustrating a semiconductor manufacturing apparatus including a wafer loading apparatus according to the present invention;

FIG. 3 is a perspective view illustrating a pusher of a wafer loading apparatus according to the present invention;

FIG. 4 is a perspective view illustrating a disk pad of a wafer loading apparatus according to the present invention;

FIGS. 5 to 8 are cross-sectional views illustrating a wafer loading method according to the present invention; and

FIG. 9 is a flow diagram illustrating a wafer loading method according to the present invention.

DETAILED DESCRIPTION

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in different forms and should not be constructed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the thickness of layers and regions are exaggerated for clarity. It will also be understood that when a layer is referred to as being “on” another layer or substrate, it can be directly on the other layer or substrate or intervening layers may also be present.

Referring to FIG. 2, a semiconductor manufacturing apparatus according to the present invention is provided, for example, an ion implantation apparatus includes a disk 110 in a substantially vertical position located in a process chamber 100 wherein an ion implantation process is substantially performed. The disk 110 is rotated at a predetermined speed during an ion implantation process. In addition, a plurality of disk pads 200 are disposed at an outer circumference of the disk 110 for loading the wafer 300.

A cassette 700, wherein the wafer 300 is loaded, which can be a vacuum cassette, is inserted into the process chamber 100 from the outside so as to supply the wafer 300 to the disk pad 200. At this time, a wafer loading from the cassette 700 to the disk pad 200, and a wafer unloading from the cassette 700 to the disk pad 200, are obtained using an arm 600. The arm 600, which can be a vacuum arm, transfers the wafer 300 to a substantially vertical position.

There is a holder 500 for removing the wafer 300 loaded on a front side of the disk pad 200. The holder 500 removes the wafer 300 from the disk pad 200 and transfers it to the arm 600 when unloading a wafer 300 from the disk pad 200 to the cassette 700. A pusher 400 is located at a rear side of the disk pad 200. The pusher 400 can be symmetrically disposed at an opposite side to the holder 500 with the disk 110 located therebetween.

FIG. 3 shows a pusher, and FIG. 4 shows a rear surface of the disk pad. Referring to FIGS. 3 and 4, the pusher 400 includes a pushing member 420 and a sensing member 440. The sensing member 440 contacts a rear surface of a wafer loaded on a front surface of the disk pad 200 to sense if a wafer is loaded. It may also include a contact sensor as hereinafter described.

A part of the clamp 220 is shown at a rear surface of the disk pad 200. A hole 240 in which the sensing member 440 is inserted is formed at the rear surface of the disk pad 200. It is preferable that the hole 240 is formed at a central portion of the disk pad 200 to more effectively sense if the wafer is closely adhered. If the hole 240 is not centered on the disk pad 200, an offset loading placement could be determined to be accurately centered even though it is not properly located on the disk pad 200.

The pusher 400 is located at a rear side of the disk pad 200, and moves the rear surface of the disk pad 200 in a forward or backward direction. The pushing member 420 advances the clamp 220 so that it is unclamped or opened by the pusher's forward movement. At the same time, the sensing member 440, for example, the contact sensor 440, is inserted through a hole to constitute the same surface as a front surface of the disk pad 200. In the meantime, the contact sensor 440 may be inserted in the hole 240 to be placed at a point higher than the front surface of the disk pad 200. Adherence of the wafer to the disk pad 200 can be controlled in accordance positioning the contact sensor 440 of the pusher 400. In the meantime, a silicon pad is formed on a front surface of the disk pad 200 (see 230 in FIG. 5).

Referring to FIG. 5, a wafer W is transferred toward the front surface of the disk pad 200 (S100). The pusher 400 is located at a rear surface of the disk pad 200.

Referring to FIG. 6, the pusher 400 moves toward a rear surface of the disk pad 200. At this time, the pushing member 420 pushes out the clamp 220 to make the clamp 220 opened or unclamped (S200). Furthermore, the contact sensor 440 is inserted in the hole 240 so that an end of the contact sensor 440 constitutes the same surface as the front surface of the disk pad 200. However, an end of the contact sensor 440 may be inserted in the hole 240 so that it is placed at a point higher than the front surface of the disk pad 200.

Referring to FIG. 7, a wafer W is loaded on a front surface of the disk pad 200 at an unclamped state (S300). At this time, the contact sensor 440 senses if a rear surface of the wafer W is adhered to a front surface of the disk pad 200 (S400).

As a result of sensing the extent of adherence, if the sensing degree of the contact sensor is satisfied as shown in FIG. 8, the pusher 400 moves backward from its original position with respect to the disk pad 200, and the clamp 220 clamps the wafer W (S500). An ion implantation process is performed after a wafer clamping (S600).

Contrary to this, if a sensing degree of the contact sensor 440 is not satisfied, the pusher 400 is interlocked at a state of being stopped (S700). In this case, a user has an opportunity to correct an unstable clamping state when an alarm signal is activated or a signal light is turned on.

The above detailed description illustrates the present invention. While the invention has been disclosed in its preferred embodiments, the specific embodiments as disclosed and illustrated herein are not to be considered in a limiting sense. Indeed, it should be readily apparent to those skilled in the art in view of the present description that the invention may be modified in numerous ways. The inventor regards the subject matter of the invention to include all combinations and sub-combinations of the various members, features, functions and/or properties disclosed herein, as defined in the attached claims. It should be appreciated that the scope of the invention is not limited to the detailed description of the invention herein above, which is intended merely to be illustrative, but rather comprehends the subject matter defined by the following claims.

As described above, according to the present invention, it is possible to exactly determine an adherence of a wafer to the disk pad by a sensor before regular processes are performed. Accordingly, wafer losses can be minimized or avoided during a process at an unstable wafer clamping state, resulting in improving productivity or a yield of a semiconductor chip. 

1. An apparatus for loading a wafer comprising: a disk pad for supporting a wafer; a member defining a hole mounted on a front surface of the disk pad for affixing the wafer to the disk pad; and a pusher positioned at the back of the disk pad, the pusher having a pushing member for moving the affixing member and a sensing member for sensing contact between the disk pad and the wafer.
 2. The apparatus of claim 1, wherein the sensing member is located within the hole at a front surface of the disk pad.
 3. The apparatus of claim 1, wherein the sensing member is in the hole at a higher point than a front surface of the disk pad.
 4. The apparatus of claim 1, wherein the sensing member is a contact sensor for determining wafer loading by locating the rear surface of the wafer loaded on the front surface of the disk pad and defining the relative degree of adhesion of the rear surface of the wafer to the disk pad.
 5. The apparatus of claim 1, wherein the hole is formed at substantially the center portion of the disk pad.
 6. A semiconductor manufacturing apparatus comprising: a rotatable disk located in a process chamber in a substantially vertical position; a plurality of disk pads mounted on a perimeter of the disk for supporting wafers, each disk pad including a clamp for engaging the wafer and a hole formed at substantially the center portion of the wafer; an arm for transferring the wafer to the front surface of the disk pad in a substantially vertical position; and a pusher positioned at the back of the disk pad, the pusher having a pushing member for moving the clamp to be unclamped and a sensing member for sensing contact between the disk pad and the wafer.
 7. The semiconductor manufacturing apparatus of claim 6, wherein the sensing member is located within the hole at the front surface of the disk pad.
 8. The semiconductor manufacturing apparatus of claim 6, wherein the sensing member is located within the hole and positioned at a higher point than the front surface of the disk pad.
 9. The semiconductor manufacturing apparatus of claim 6, wherein the sensing member is a contact sensor for determining wafer loading by locating the rear surface of the wafer loaded on the front surface of the disk pad and defining the relative degree of adhesion of the rear surface of the wafer to the disk pad.
 10. The semiconductor manufacturing apparatus of claim 6, further comprising a holder positioned at the front surface of the disk for releasing the wafer from the disk pad.
 11. The semiconductor manufacturing apparatus of claim 10, wherein the holder and the pusher are symmetrically located on opposite sides of the disk.
 12. A wafer loading method comprising: providing a wafer and a disk pad; transferring the wafer to the disk pad; providing a pusher; moving the pusher toward the back of the disk pad; loading the wafer to the disk pad; and clamping the wafer by moving the pusher from the disk pad until the wafer is adherely engaged with the disk pad.
 13. The wafer loading method of claim 12, comprising further interlocking enaging the wafer so that it is more closely adhered to the disk pad.
 14. The wafer loading method of claim 12, which further comprises sensing contact between the disk pad and the wafer.
 15. The wafer loading method of claim 12, further comprising transferring the wafer to the front surface of the disk pad in a substantially vertical position.
 16. A method for loading a wafer on a front surface of the disk pad using an apparatus comprising a disk pad for supporting a wafer, the disk pad having a fixing member mounted on a front surface thereof for fixing the wafer and a hole extending therethrough; and a pusher positioned at the back of the disk pad, the pusher having a pushing member for moving the fixing member fixing and a sensing member for sensing a contact between the disk and the wafer: transferring the wafer to the front surface of the disk pad; moving the pusher toward the disk pad so that the pushing member of the pusher moves the fixing member to be unclamped, and inserting the sensing member into the hole to constitute the same surface as the front surface of the disk pad; loading the wafer on the front surface of the disk pad; and moving the pusher from the disk pad so that the fixing member fixes the wafer to the front surface of the disk pad, when the sensing member contacts the rear surface of the wafer.
 17. The method of claim 16, further comprising interlocking a wafer loading if the sensing member does not contact the rear surface of the wafer.
 18. The method of claim 16, comprising further interlocking enaging the wafer so that it is more closely adhered to the disk pad.
 19. The method of claim 16, which further includes the step of sensing contact between the disk pad and the wafer.
 20. The method of claim 16, further comprising transferring the wafer to the front surface of the disk pad in a substantially vertical position. 